A variety of organic compounds are usefully introduced into a vacuum system to coat substrates. For example, styrene can be heated above its boiling point (145-146.degree. C.), fed into a plasma glow discharge, and deposited as a replica film on a specimen for electron microscopy, as disclosed in U.S. Pat. No. 4,447,374, issued May 8, 1984, inventor Tanaka. A delivery system for delivering hexamethyldisilazane vapor by a carrier gas or vacuum suction in the range of one Torr has recently been described by a product data sheet of J. C. Schumacher Company, Oceanside, Calif. This delivery system is used in semiconductor photolithography processing as a priming agent to enhance photoresist adhesion during wafer patterning.
Sacher et al., U.S. Pat. No. 4,557,946, issued Dec. 10, 1985, describes use of plasma polymerized coatings from organosilicon compounds to form a moisture barrier on the substrate by heating the substrate and controlling the plasma power level. Wertheimer et al., U.S. Pat. No. 4,599,678, issued July 8, 1986, discloses use of an organosilicon in a glow discharge to coat thin film capacitors when these substrates are heated to a temperature in excess of 50.degree. C.
Vaporizing systems for such glow discharge uses have sometimes introduced the vapor through a needle valve, and the liquid has typically been vaporized either by simply heating a liquid reservoir or in response to the pressure difference when coupled to a vacuum system.
These prior known devices do not provide for a precisely controlled, substantially continuous and monitored delivery of vapor flow into an associated vacuum system.